A. Field of the Invention
The present invention relates to a tool suitable for lifting and maneuvering utility access covers. It appears to be especially useful in connection with manhole covers that are formed with no holes that go all the way through the manhole lid.
B. Description of the Art
It is well known that many utility installations (e.g. sewer pipes, electrical cable conduits, and the like) are positioned below ground level. Access to these utility installations is generally achieved by climbing through an entrance hole at the ground level and down a vertically extending access conduit. This access conduit is usually a cylindrical pipe having a diameter large enough to permit a person to gain access to the utility installation. Such access conduits are commonly called "manholes".
The access conduit entrance is invariably provided with a cover (the manhole lid). For safety, security and durability, this lid is usually fabricated from a rigid material such as cast iron. As a result, it is very heavy and difficult to lift.
Primarily to prevent rainwater and dirt from entering the access conduit, many of the manhole covers which are now being manufactured do not have any holes that go all the way through them. Instead, they are formed with recesses in their top surface at the 6 o'clock and the 12 o'clock positions of the outer circumferential edge of the cover.
One technique that has been tried for lifting or maneuvering these very heavy covers includes the use of crow bars (or similar rod-like tools) which are inserted into one of these recesses. This relies on friction between the cover and the tool to affect the lifting of the cover. Alternatively, the cover may be removed by forcing the cover out of its support ring by jamming such a tool between the outer edge of the cover and the support ring. In both instances, very little control over the movement of the cover can be maintained, and there is a significant risk of injury to the operator.
The art has therefore attempted to develop a better manhole lid lifter. See e.g. U.S. Pat. Nos. 1,933,384, 2,348,978, 2,655,399, 2,832,628, 4,277,731 and 4,365,925. However, none of these devices has lowered the risk of injury to an acceptable level.